Fig. 1: Behaviour is associated with dopamine transients in DLS.

a, dLight expression and fibre placement in DLS (Methods). b, The behavioural characterization pipeline using MoSeq (n = 14 mice for MoSeq, 216 experiments; Methods). c, Examples of measured kinematic variables. d, Aligned kinematic variables, MoSeq syllables and dLight fluorescence from an example experiment. e, Top, average correlation between kinematic variables and dLight transient rate. Bottom, correlations with dLight fluorescence. Coloured shading denotes bootstrapped s.e.m.; grey shading indicates the 95% shuffle confidence interval. Solid bars indicate statistical significance at P < 0.05 (shuffle test; Methods). f, Top, average fluorescence (z-scored to shuffle; Extended Data Fig. 4c and Methods) aligned to movement initiation or syllable onsets (n = 100 shuffles). The average syllable-associated dLight transient exceeds that associated with movement initiation (P = 0.0006, z = 3, effect size r = 0.8, two-sided Wilcoxon signed-rank test; n = 14 averages). Bottom, derivative of top panel. Green shading represents the 95% bootstrap confidence interval; grey shading represents the 95% shuffle confidence interval. g, The distribution of all syllable-associated dLight peaks. Bottom, the cumulative distribution. h, Left, the distribution of syllable-associated dLight peaks for across all experiments. Right, z-scored average syllable-associated waveforms, sorted by peak fluorescence. The blue and red stars indicate the syllable waveforms shown in k. ***, Kruskal–Wallis H test on average syllable-associated fluorescence amplitudes: P < 10⁻²⁵, H = 209.29, n = 518 mouse–syllable pairs. y-axis syllable sorting is shared across panels. i, Left, example syllables with different average (across experiments) waveforms (top) but similar velocity (bottom). Right, example syllables with similar waveforms (top) but different velocities (bottom). Shading represents the 95% confidence interval. j, Robust linear regression between syllable-associated dLight and velocity (top) or angular velocity (bottom; Methods). Each point is a sampled syllable instance (n = 28,000 points; n = 2,000 points per syllable drawn randomly from each mouse). Regression line (shading indicates the 95% bootstrap confidence interval) and kernel density estimate are shown. P-values estimated by shuffle test. k, Left, average syllable-associated waveforms for starred syllables in h (right). Coloured shading represents the 95% bootstrap confidence interval; grey shading represents the 95% shuffle confidence interval. Right, syllable-associated waveforms from the left panel binned into quartiles of peak magnitudes. l, Left, held-out classifier performance predicting syllable identity from syllable-associated dLight peak amplitudes (top) or waveforms (bottom). Right, dendrogram showing syllables organized by MoSeq distance (Methods). AU, arbitrary units.